Acrylonitrile Butadiene Styrene
Acrylonitrile Butadiene Styrene (ABS), it is a dark thermoplastic and amorphous polymer. It is a terpolymer (copolymer comprising of three unmistakable monomers) of Acrylonitrile, Butadiene, and Styrene. Together they make an item that is adaptable and light in weight that can be shaped into numerous things that we use in our regular day to day existences.
The benefit of ABS is that an assortment of changes can be had to enhance impact protection, sturdiness, and heat protection. Molding at a high temperature enhances the gleam and heat protection of the item while molding at a low temperature is where the highest impact resistance and strength are obtained.
Polyethylene
Polyethylene is a thermoplastic polymer with variable crystalline structure and a huge scope of uses relying upon the type. It is a standout amongst the most adaptable and most famous plastics on the planet since the 1950s when it was produced by German and Italian researchers. The two most regular kinds of this plastic are high-thickness polyethylene (HDPE) and low-thickness polyethylene (LDPE).
The upsides of polyethylene are abnormal amounts of pliability, rigidity, impact protection, protection from dampness, and recyclability. The higher the thickness of the polyethylene material utilized the more grounded, more unbending, and more heat safe the plastic is. The essential employments of polyethylene are plastic sacks, plastic films, compartments including bottles, and geomembranes.
Polyamide (Nylon)
Nylon material is utilized as a part of a vast scope of various applications in view of its electrical properties, sturdiness, wear protection and chemical protection being very noteworthy. Nylon has an abnormal state of strength and is impervious to numerous outer components like scratches, impact, and chemicals. This material produces plastic parts utilized as a part of numerous businesses, for example,
Medicinal items
Car items
Games hardware
Attire and footwear
Industrial components
High Impact Polystyrene
High Impact Polystyrene (HIPS) is a prevalent and intense plastic that is in the Polystyrene family. Polystyrene is weak and can be more impact safe if joined with different materials. It is made from modifying crystal styrene with rubber which helps to give it many levels of impact resistance. It is low cost, has good dimensional stability and rigidity. There are FDA grades available since it is non-toxic and used as containers for many food goods.
It is exceptionally flammable, yet there are fire resistant and polished evaluations that are generally utilized for injection molding.
Polypropylene
This is an extremely regular plastic that is known for its adaptability. PP (polypropylene) is an exceptionally unique plastic and has been intensified for an extensive variety of properties. A few attributes of this plastic are its high liquefying point, high protection toward stress and splitting, magnificent impact quality, and does not break down from responses with water, acids, and cleansers.
PP is ok for use as food holders since it doesn’t filter chemicals into nourishment items. It can be generally found in family unit merchandise, for example, utensils, athletic clothing, area rugs, and car parts, for example, auto batteries.

A brake which uses air as a working fluid is known as pneumatic brake. The system actuated to apply this phenomenon is know as pneumatic brake system.
An pneumatic brake system or a compressed air brake system is a type of friction brake for vehicles in which compressed air pressing on a piston is used to apply the pressure to the brake pad needed to stop the vehicle.
Construction of pneumatic braking system
The simplest air brake system consists of
An air compressor
A brake valve
series of brake chambers at the wheels
unloader valve
A pressure gauge and a safety valve
and an air reservoir.
These are all connected by tubes.
Some air braking systems may have additional components such as
stop light switch
low pressure indicator
An air supply valve to supply air for tyre inflation
A quick release air quickly from the front brake chambers when the brake pedal is released
A limiting valve for limiting the maximum pressure in the front brake chambers and a relay valve to help in quick admission and release of air from the rear brake chambers.
Working of pneumatic braking system
The air compressor operated by the engine forces air at a pressure of 9-10 kscm (kilo standard cubic meters) through the water and oil separator to the air reservoir.
The air pressure in the reservoir is indicated by a pressure gauge.
The reservoir contains enough compressed air for several braking operations. From the reservoir the air is supplied to the brake valve.
As long as brake pedal is not depressed, brake valves stop the passage of air to brake chambers and there is no braking effect.
When the brake pedal is depressed, the brake valves varies its position and compressed air is admitted into the wheel brake chambers.
In the chambers the air acts upon flexible diaphragms, moves them the pushes out the rods connected with the levers of the brake gear cams.
The cams turn and separate the shoes thus braking the wheels.
When the brake pedal is released, the supply of compressed air is cut off from the brake chambers and they are connected to the atmosphere.
The pressure in the chambers drops, the brake shoes are returned to their initial position and the wheels run free.
The brake valve is equipped with a servo mechanism which ensures that the braking force on the shoes is proportional to the force applied to the pedal.
Besides the valve imparts a relative reaction to the movement of the pedal so that the driver can sense the degree of brake application.
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Any device which can convert heat energy of fuel into mechanical energy is known as engine or heat engine. Engine is widely used in automobile industries or we can say that engine is the heart of an automobile. Basically engine may be classified into two types.
1. External combustion (E.C.) Engine
2. Internal Combustion (I.C.) Engine
Types of Engine:
1. External combustion (E.C.) Engine
It is an engine in which combustion of fuel take place outside of the engine. In this type of engine heat, which is generated by burning of fuel is use to convert the water or other low boiling temperature fluid into steam. This high pressure steam used to rotate a turbine. In this engine we can use all solid, liquid and gases fuel. These engines are generally used in driving locomotive, ships, generation of electric power etc.
Advantages of E.C. engine-
In these engines starting torque is generally high.
Because of external combustion we can use cheaper fuels as well as solid fuel.
They are more flexible compare to internal combustion engines.
2. Internal Combustion (I.C.) Engine
It is an engine in which combustion of fuel take place inside the engine. When the fuel burns inside the engine cylinder, it generates a high temperature and pressure. This high pressure force is exerted on the piston (A device which free to moves inside the cylinder and transmit the pressure force to crank by use of connecting rod), which used to rotate the wheels of vehicle. In these engines we can use only gases and high volatile fuel like petrol, diesel. These engines are generally used in automobile industries, generation of electric power etc.
Advantages of I.C. engine-
It has overall high efficiency over E.C. engine.
These engines are compact and required less space.
Initial cost of I.C. engine is lower than E.C. engine.
This engine easily starts in cold because of it uses high volatile fuel.
Types of I.C. Engine
I.C. engine is widely used in automobile industries so it is also known as automobile engine. An automobile engine may be classified in many manners. Today I am going to tell you some important classification of an automobile engine.
According to number of stroke:
1. Two Stroke Engine
In a two stroke engine a piston moves one time up and down inside the cylinder and complete one crankshaft revolution during single time of fuel burn. This type of engine has high torque compare to four stroke engine. These are generally used in scooters, pumping sets etc.
2 Four Stroke Engine .
In a four stroke engine piston moves two times up and down inside the cylinder and complete two crankshaft revolutions during single time of fuel burn. This type of engines has high average compare to two stroke engine. These are generally used in bikes, cars, truck etc.
According to design of engine:
1. Reciprocating engine (piston engine)
In reciprocating engine the pressure force generate by combustion of fuel exerted on the piston (A device which free to move in reciprocation inside the cylinder). So the piston starts reciprocating motion (too and fro motion). This reciprocating motion converts into rotary motion by use of crank shaft. So the crank shaft starts to rotate and rotate the wheels of vehicle. These are generally used in all automobile.
2. Rotary engine (Wankel engine)
In rotary engine there is a rotor which frees to rotate. The pressure force generate by burning of fuel is exerted on this rotor so the rotor rotate and starts to rotate the wheels of vehicle. This engine is developed by Wankel in 1957. This engine is not used in automobile in present days.
According to fuel used:
1. Diesel engine
These engines use diesel as the fuel. These are used in trucks, buses, cars etc.
2. Petrol engine
These engines use petrol as the fuel. These are used in bikes, sport cars, luxury cars etc.
3. Gas engine
These engines use CNG and LPG as the fuel. These are used in some light motor vehicles.
4. Electric engine
It is eco-friendly engine. It doesn’t use any fuel to burn. It uses electric energy to rotate wheel.
According to method of ignition:
1. Compression ignition engine
In these types of engines, there is no extra equipment to burn the fuel. In these engines burning of fuel starts due to temperature rise during compression of air. So it is known as compression ignition engine.
2. Spark ignition engine
In these types of engines, ignition of fuel start by the spark, generate inside the cylinder by some extra equipment. So it is known as spark ignition engine.
According to number of cylinder:
1. Single cylinder engine
In this type of engines have only one cylinder and one piston connected to the crank shaft.
2. Multi-cylinder engine
In this type of engines have more than one cylinder and piston connected to the crank shaft.
According to arrangement of cylinder:
1. In-line engine
In this type of engines, cylinders are positioned in a straight line one behind the other along the length of the crankshaft.
2. V-type engine
An engine with two cylinder banks inclined at an angle to each other and with one crankshaft known as V-type engine.
3. Opposed cylinder engine
An engine with two cylinders banks opposite to each other on a single crankshaft (V-type engine with 180o angle between banks).
4. W-type engine
An engine same as V-type engine except with three banks of cylinders on the same crankshaft known as W-type engine.
5. Opposite piston engine
In this type of engine there are two pistons in each cylinder with the combustion chamber in the center between the pistons. In this engine a single combustion process causes two power strokes, at the same time.
6. Radial engine
It is an engine with pistons positioned in circular plane around the central crankshaft. The connecting rods of pistons are connected to a master rod which, in turn, connected to the crankshaft.
According to air intake process:
1. Naturally aspirated
In this types of engine intake of air into cylinder occur by the atmospheric pressure.
2. Supercharged engine
In this type of engine air intake pressure is increased by the compressor driven by the engine crankshaft.
3. Turbocharged engine
In this type of engine intake air pressure is increase by use of turbine compressor driven by the exhaust gases of burning fuel.

The boiler system comprises a feed-water system, steam system, and fuel system. The feed-water system supplies treated water to the boiler and regulate it automatically to meet the steam demand. Various valves and controls are provided to access for maintenance and monitoring.
The steam system heats and vaporizes the feed water and controls steam produced in the boiler. Steam is directed through a piping system to the application. Throughout the system, steam pressure is regulated using valves and monitored with steam pressure gauges.
The fuel system consists of all equipment used to supply of fuel to generate the necessary heat. The equipment required in the fuel system depends on the type of fuel used in the system.
Boilers Classification:
There are a large number of boiler designs, but boilers can be classified according to the following criteria:
1. According to Relative Passage of water and hot gases:
Water Tube Boiler: A boiler in which the water flows through some small tubes which are surrounded by hot combustion gases, e.g., Babcock and Wilcox, Stirling, Benson boilers, etc.
Fire-tube Boiler: The hot combustion gases pass through the boiler tubes, which are surrounded by water, e.g., Lancashire, Cochran, locomotive boilers, etc.
2. According to Water Circulation Arrangement:
Natural Circulation: Water circulates in the boiler due to density difference of hot and water, e.g., Babcock and Wilcox boilers, Lancashire boilers, Cochran, locomotive boilers, etc.
Forced Circulation: A water pump forces the water along its path, therefore, the steam generation rate increases, Eg: Benson, La Mont, Velox boilers, etc.
3. According to the Use:
Stationary Boiler: These boilers are used for power plants or processes steam in plants.
Portable Boiler: These are small units of mobile and are used for temporary uses at the sites.
Locomotive: These are specially designed boilers. They produce steam to drive railway engines.
Marine Boiler: These are used on ships.
4. According to Position of the Boilers:
Horizontal, inclined or vertical boilers
5. According to the Position of Furnace
Internally fired: The furnace is located inside the shell, e.g., Cochran, Lancashire boilers, etc.
Externally fired: The furnace is located outside the boiler shell, e.g., Babcock and Wilcox, Stirling boilers, etc.
6. According to Pressure of steam generated
Low-pressure boiler: a boiler which produces steam at a pressure of 15-20 bar is called a low-pressure boiler. This steam is used for process heating.
Medium-pressure boiler: It has a working pressure of steam from 20 bars to 80 bars and is used for power generation or combined use of power generation and process heating.
High-pressure boiler: It produces steam at a pressure of more than 80 bars.
Sub-critical boiler: If a boiler produces steam at a pressure which is less than the critical pressure, it is called as a subcritical boiler.
Supercritical boiler: These boilers provide steam at a pressure greater than the critical pressure. These boilers do not have an evaporator and the water directly flashes into steam, and thus they are called once through boilers.
7. According to charge in the furnace.
Pulverized fuel,
Supercharged fuel and
Fluidized bed combustion boilers.